This book is based on a doctoral thesis submitted to the University of Bern in thesummerof2002. Researchonthethesiswasmadepossiblethroughagrant provided by the Swiss National Science Foundation (SNF) from 2000 to 2002 foraprojectonthehistoryandepistemologyofscienti?cillustrations(Project No. 1152-059499). Gerd Gra ho? headed this programme at the University of Bern and made my reworking of the thesis into a book in English possible. He also provided...